Singapore granted its highest number of citizenships last year in more than a decade, even as it has tightened its intake of permanent residents (PRs) in recent years.

In all, 20,693 became Singaporeans last year, Minister in the Prime Minister's Office Grace Fu revealed yesterday in Parliament.

This is higher than the previous year's 15,777 and follows an uptrend in the number of new citizens.

Between 1987 and 2006, about 8,200 people were given citizenship papers a year. From 2007 to 2011, that number grew to 18,500 a year, according to statistics previously released by the National Population and Talent Division (NPTD).

An NPTD spokesman told The Straits Times yesterday that the number of citizenships granted each year fluctuates depending on factors such as the number and quality of applicants.

Last year's successful applications were within the 15,000 to 25,000 range it expects to grant yearly, she said.

The lower number of new citizenships granted in 2011, she noted, was due to the introduction of the Singapore Citizenship Journey, a programme to help new citizens better appreciate the country's history, norms and values. "This process takes about two months to complete. Hence, about 4,000 applicants who began their citizenship formalities in late 2011 were only granted citizenship in early 2012," she said.

Last year's new citizenship figure also includes 2,735 minors under the age of 21, most of whom were born overseas to Singaporean parents, Ms Fu said.

Excluding minors, eight in 10 new citizens who took the oath last year had lived in Singapore for more than five years, while five in 10 had been here for more than a decade, Fu said.

To Dr Neo, who felt that only those contributing to society and "not draining our limited resources" should become new citizens, Fu gave assurances that a set of selection criteria is in place.

She assured Ong that citizenships are not granted to people before they start living here. But exceptions are made for some dependants, she said.

"These are all considered as a family unit and, from time to time, their children, their wives, their parents may be granted Singapore citizenship before they have a long extended period of stay in Singapore."

Fu also revealed that 4,100 new citizens a year were foreign spouses sponsored by Singaporeans, while another 4,100 spouses became permanent residents. These figures are averaged over 2008 to last year. The bulk were foreign wives of Singaporean husbands - nine in 10 for new citizens and eight in 10 for permanent residents.

Rejections made up 10 per cent of applications for citizenship, or 580 a year, but slightly more than half of applications for PRs - or 4,400 a year.

Baey was concerned for these Singaporeans whose spouses do not meet the conditions to stay on as PRs.

"Are they expected to migrate, leave Singapore or maybe they shouldn't marry a foreigner in the first place?" he asked.

Fu acknowledged the difficulty that comes with matters of the heart, like marriage, but added: "Hard as it may be, we need to have certain rules.

"We have to make sure that the immigrants that we take in do not strain our financial resources and also... have a very good chance of assimilating into our society."

She added that the spouses still get long-term social visit passes to stay on and, over time, if the Singaporean partner is able to support his family and the marriage is stable, their chances of approval are higher than that of those without family nor children.